Block for sectional grinding wheels



Aug. 18, 1936. F. c. PENNY I BLO C K FOR SECTIONAL GRINDING- WHEELSFiled Oct. 16, 1934 lyvENTOR ATTO R N EYS Patented Aug. 18, 1936 UNITEDSTATES PATENT. OFFICE The Bridgeport Safety Emery Wheel Com pany, Inc.,Stratford, Conn, a corporation of- Connecticut Application October 16,1934, serial'Norvisass 6 Claims. (01.51-20'9) v flanges is divided intoa plurality of pockets by This invention relates to new and usefulimprovement in blocks for sectionalgrinding wheels of the type shown inpatents to Hyde, Numbers 1,133,475- and 1,589,855 of March 30, 19-1 5,and June 22 1926, respectively.

An object of the invention is to provide animproved construction of shoefor the blocks ofa sectional grinding wheel. More specific objects ofthe invention are to provide a shoe for a block of a sectional grindingwheel and which shoe is light in weight and comprises aminimum of metaland may be manufactured at low cost whereby it need notbe returned tothe factory for refilling when the abrasive blockis worn down.

Additional objects are to provide a-shoe a'sindicated and which isso'constructed asto be firmly attached to the block to which it ismoulded, and which does not materially" detract from the cross sectionofthe block in its shearing zone, and whichprovides means whereby amarker plug may be moulded directly into the abrasive block on its innerend. I i .i Other objects and advantages will'become apparent from aconsideration of the'following de-' tailed description taken inconnection with the accompanying drawing wherein a satisfactoryembodiment of the'inven'tion is shown. However, it will be understoodthat the invention is not limited to the details disclosed but includesall such variations and modifications as fall within the spirit of theinvention and the scope of the appended claims;

In the drawing: v Fig; 1 is a front elevational view showing a portionof a sectional grinding wheel;

Fig.- 2' is a sectional view taken substantially along the'plane of theline 22 of Fig. 1; Fig. 3 is a front elevation'al view, on-an enlargedscale, showing an abrasive block andshoe; with part of the abrasiveblockbroken away;

. Fig. 4' is'a sectional view taken' substantially along the plane ofthe line 44' ofFig. 3;

' Fig; 5 is a rear elevational view of the shoe alone, on the scale ofFig.3; and

.Fig. 6 is a detail-sectional view taken substantially along the planeof the linefi -liof Fig.3. Referring in detailt'othe drawing a portionof a sectional grinding wheel is shown at It] and theisame compri'ses'a;supportincluding a carry ing disc ll having ahub l2 for attachmenttoasha'ft', a portion ofwhich isshown at l3, and said inner peripheraledge 2T the body and flange 2B transversely extending divisional webs ormemhers I! which are secured-in place in any suitable manner; 'I-hewheel I is assembled with two grinding blocks [-6 ineachepockeh-andsuchblocks are r ferably shaped in cross section substan-' tially asbestshown' in Fig;- 1 although not necessarily' so.- Blocks l-6 aresecured "or clamped in position by means of tapered wedges l8' in thespaces betweentwo adjacent locksand the wedges 10 are adjusted byscrews- 18 passed through the inner flange M'of'the supportandsuchscrews are locked-in adjusted position as by nuts 20: 7 Thesewedges clamp the blocks against the flange I5 and Webs I 1. I

7 Each grinding blockl6 includes an abrasive block or portion 21 and ametal shoe 22"secur'ed to theiiiner end of the abrasive portion as bybeing moulded thereto.- Shoe'22 is in the form of anopenffame-likestructure incl'udingabo y portion- 23 having inner andouter peripheral edges. An outer flange 24 extends forwardly from theouter edge of the body 23 and such flange is tapered o'nitsf innefsid'e"2 5 whereby it is thinnest at'its-for'war'd or"fre'eedge. Afiang'e26extends forwardly from the inner'peripheral edge of the body 23 andthis-flange in addition to extendirfg fo'rw'ar'dl'y ir'iclines' inwardlyof the shoe or in adirection aweynom the outer flange'24 Gn its have aemmuous' tap'er from the forward or free edge ofthe flange 26throughtofthe r'ear'surface' of the body.

' As 'here' shownfa rib 28'" extends transversely across the bodyandsuch rib -may be centrally '5 enlarged and in such enlargedjportionprovided with atapped opening 295 The inner flange 26 (innate- 1yextends along" the opposite sides of rib 28'; andwhere such flange is onthe rib it is deslgn'ated fifariditisfhfther noted that the continuo-u'sta'p'er 2-1 is-carried outon the portion 30 of the flange whereori thetapered surface'is designatd flli From thisit- Will beunderstoodthat-looking into the-froiit*of-the-shoe 22 as in Fig Q3 tIie oppo'sedsurfaces 'of the'flanges 24 and 26 inenne a'wayrrom one-jano'therandthatthe flange-portions 30 of the'rib-28 incline away from theme;- W

Whenthe' abrasive-material 21 is moulded to the Slide '22 to fo rma'c0mp1 e t e blOCk the said mater al'entersinto the-spaces between theflanges zt' and z'e 'and-also enters the openings 32-and 33 through therraine-nkeibody or theslio'e. It will be understood that the rib- 2adivides the space through the shoe into twoparts whereby thetwo openings32 and 33 are formed. The abrasive material entering the openings 32 and33 in the body of the shoe passes to the rear of the flange 26 andcompletely fills the openings, entering under the inclined surfaces 21which as above stated extend from the forward or free edges of theflanges 26 to the rear surface .of the body of the shoe. From Fig. 4 itwill be clear that the material thus interlocks with the shoe in such amanner that when the material is set and hardened the shoe and theabrasive material are bound or moulded together with the shoe dovetailedto the abrasive material by means of the flange 2B and the inclined rearsurface portions 21.

When the block it is being moulded a marker, plug 34 may be moulded intothe rear end of the abrasive material. This is accomplished simply bydisposing the plug in one or the other of the openings 32 and 33 withthe plug facing toward the rear of the shoe 22. That is as the block is,molded with the shoe in a horizontal position with surface 23 restingon the bottom of the flask the disc 34 is merely placed face down onthis bottom within one of the openings 32 or 33 and then the plasticabrasive material molded onto the shoe and the disc. In this way a. plugcarrying marks indicating the grade and grain size of the abrasivematerial is moulded into the completed abrasive block so that the blockis permanently identified, the marker plug being so located as not to beworn away as the block is used but is easily visible. 7 The threadedopening 29 of each shoe receives an adjusting screw 35 and the abrasiveportion 2| of theblock is provided with an opening 36 accommodating thescrew. The screw of each block passes through an opening 31 in the discll and has a flange 38 engaging the inner wall of the disc wherebymovement of the screw in one direction is limited. On the opposite sideof the disc is a lock-plate 39 which is forked at one end so as to bepassed into an annular groove 40 in the screw 35 wherebyto preventwithdrawal of the screw. Plate 39 is secured to the support as by ascrew 4| which must, of course, beloosened before the plate may beshifted. If no'adjusting screw is used the tapped opening 29 may beomitted.

The manner of adjusting the blocks 16 is described in my patents abovereferred to and forms no particular part ofthe present invention. The

present invention relates to the shoe 22 and the abrasive block moldedto it and it will be noted that since the shoe is in the form of an openframe it includes but a minimum of metal and is light in weight. As theinner flange 26, which may be continuous or may be interrupted as by therib 28, enters into the abrasive material 2| at an angle or so as toform a dove-tail connection, with portions of the abrasive material atboth the front and rear sides of the flange, it will be appreciated thatthe material 2| and shoe 22 are securely locked together.

Shoe 22 may be a casting or a pressed or forged shoe, and when cast maybe moulded without the use of cores. This is true since the pattern maybe easily withdrawn from the sand in which either of its faces ismoulded, that is, on the rear face of the shoe there is but the onecontinuous incline 21 and on the forward face of the shoe 1 the opposedsurfaces of the flanges 24 and 26 taper or incline away from one anothertoward their free edges. It can therefore be molded with straight drawson the pattern. Since the shoes include but little metal and since theymay be cheaply moulded without the use of cores they represent verylittle loss when thrown away after the abrasive block is worn down.These shoes may be manufactured at such prices that it is not necessarythat they be returned to a factory for refilling after the originalabrasive block to which they were moulded has been worn away. Theshearing zone or section in the blocks l6 would be at the forward edgeof the outer flange 24 of the shoe. That is, the shearing section is thecross section of the abrasive block at the edges of flanges 24 so itwill be seen it is practically the full cross section of the block. Inthe present shoe or with the present shoe this shoe and the abrasiveblock are firmly secured together without having any inwardly extendingprojection on the free edge portion of the outer flange 24 of the shoe.In fact, this flange is thinnest at its free or forward edge so that thecross section of the abrasive portion 2! is not materially reduced inits shearing zone or section, which zone, as above explained, is at thefree edge of the flange 24. Therefore, with the present construction theabrasive portion of the block may be worn down further or a greater partof said portion of the block may be used, with little dang ger of theblock shearing off or breaking. This fact coupled with the fact that theshoes 22 contain but a minimum of metal and may be easily mouldedwithout the use of cores makes it reasonable to discard the shoe of ablock when the abrasive is worn down, and not return the block to thefatcory for refilling. Further, as above explained, with the presentshoe a marker plug such as 54 may be moulded into the-inner end of theabrasive block or in that portion of the abrasive block extendingthrough the rear face of the shoe, so that it will be readily visible toan operator or other workman positioning the blocks on a support, and itis not necessary to markthe shoe or cut or mold these marks in theabrasive itself. Having thus set forth the nature of my invention, whatI claim is:

1. In a block fora sectional grinding wheel,

a metal shoe, a block of abrasive material moulds ed ontosaid shoe, saidshoe comprising a framelike structure open at both the front and backsides thereof comprising a body having inner peripheral edges about theopening in the back and outer peripheral edges about the outside of theframe, inner and outer forwardly projecting flanges on said body at saidedges, said inner flange inclining inwardly of the body away from theouter flange and having its rear wall inclined outwardly toward the rearsurface of the body.

2. In a shoe for a block of a sectional grinding wheel, a frame-likestructure open ,at the front and rear comprising a body having innerperipheral edges about the opening through the back and outer peripheraledges about the outside of the frame, a rib extending across the bodyand connecting a pair of portions thereof, .said rib having a tappedopening therein, a forwardly projecting flange at the outer edge of saidbody, a flange at the inner edge of the body and at each side of saidrib and incliningforwardly of ripheral edges about; the opening throughthe back and outer peripheral edges about the outside of the frame, aforwardly extending flange at the inner edge of said body, said flangeinclining in a direction away from the outer edge of the body, and therear wall of said flange being inclined outwardly from its free edge.

4. In a shoe for a block of a sectional grinding wheel, a frame-likestructure comprising a body open at the front and rear having inner andouter peripheral edges, inner and outer forwardly projecting flanges onsaid body at said edges, said inner flange inclining away from the outerflange, the inner surface of said outer flange being inclined outwardlywhereby the flange is thinnest at its forward edge, and the rear wall ofsaid inner flange being inclined rearwardly in the opposite direction.

5. In a shoe for a block of a sectional grinding wheel, a frame-likestructure comprising a body open at the front and rear having inner andouter peripheral edges, inner and outer forwardly projecting flanges onsaid body at said edges, said inner flange inclining away from the outerflange, the inner surface of said outer flange inclined outwardlywhereby it is thinnest at its forward edge, said inner flange extendingabout the inner edge of said body and having a rear. wall inclinedoutwardly and rearwardly from its inner edge.

6. In a shoe for a block of a sectional grinding wheel, a frame-likestructure comprising a body open at the front and rear having. inner andouter peripheral edges, a rib extending across the body and connecting apair of portions thereof, said rib having a tapped opening therethrough,a forwardly projecting flange at the outer edge of said body, a flangeat the inner edge of the body extending forwardly and inclining awayfrom the outer flange, with its rear wall inclined outwardly andextending to the rear surface of the body.

FRANK C. PENNY.

